Winthrop k



APPLICATION FILED 1mm; i915.

h \W Q R W w nm M MN L M a 5 a \N F? hicle, with the added thereto.

a citizen of the United .AIITOMATIC TRAIN-CONTROL SYSTEM.

Application filed January 21, 1915. Serial To all whom it may concern:

Be it known that I, WINTHROP K. Howe, States, and a resident of the cityof Rochester, in the county of Ionroe and State of New York, haveinvented new and useful Improvements in Automatic Train-Control Systems,of which the following is a specification.

This invention relates to improvements in systems for automaticallycontrolling movable vehicles, particularly such vehicles as railway carsand trains.

he primary object of this invention is the production of an improvedautomatic train controlling system. Other specific objects andadvantages will appear as the-description of the invention progresses,and'the novel features of the invention will beparticularly pointed outin the appended claims.

In describing the invention in detail reference is bad to theaccompanying drawing, comprising a single figure, which is a schematicillustration of a railway track with two cars thereon, each of which isequipped with a train controlling device.

1 and 2 designate the two rails of a railway track, upon which railwayvehicles are 'movable.'

In the schematic view two vehicles are shown connected b a coupling 4.Each vehicle is represented as including two wheels and an axle. Thewheels and axle of one vehicle are designated by 5, Sand 7 respectively,and the wheels and axle of the other car by 5 6 and 7 respectively. Eachvehicle has the ordinary journal boxes, as 8 and 8 supporting a sidebar, as 9 and 9 The parts associated with the vehicle shown at the rightin the drawing are given the same reference characters as thecorresponding parts associated with the other .ve-

distinctive exponent 1 Each side bar 9 supports, by means of aprojection, as 10, a shoe, as 11, of-an'y ordinary and proper form. Theshoes, as 11,

are loosely mounted in the projection 10 and l have a collar 12rigidlyattached thereto,be-

tween whichand the projection 10 is positioned a spring 13, which causesthe shoe to normally move downward asfar as permitted by on the vehicleat the right of thefigure.

Specification of Letters IPatent.

. moved upwardly by .rotor 23 of by the enlarged upper end 14,413 shownPatented June 27, 1922. N 3,469.

The side bars, as 9, also support the two members 15 and 16 of a circuitcontroller, which, due to the resiliency of the member 15, assumes theclosed position when the shoes, as 11, are in their lower position, andwhich is opened by the contact of the upper end 14 of the shoes, as 11,when the shoes are contact'with a ramp, as 17, positioned along thetrackway.

Each car of the train has positioned thereon a translating device, as19, which is 0pperable only by current of a particular char- 'acter,such, for instance, as'alternating current. In the form shown thetranslating device 19 consists of a stator member, 20, having two poles.21 and 22 positioned directly opposite each allow the positioningtherebetween of a any proper construction. diagonally opposite portionsand 22 have placed thereon continuous bands of conducting material, 24and '25, which will be recognized by those skilled in the art, as thewell known shading-coils. The stator 20 has placed thereon theenergizing coil 26. The description of the translatin device 19 will berecognizedy by those skilled vin the 70. other and separated soas to TheI of the poles 21- p signalling art, as that of a well known alternatingcurrent motor, which has been illustrated'in the drawings and describedin this specification as one form of translating dev1ce which may beused-by applicant to put his invention into practice.

he rotor 23 is connected with, and when it moves, causes a movement ofarm 27 which at its outer end has a portion of magnetic material 28attached thereto, which when moved into the position shown. in the Idrawings, is in operative relation with the core of the direct currentelectromagnet 29, so that if the electromagnet 29 is energized themember 28 will be held in the-position shown. The electromagnet 29is.not so positioned in relation to the member 28 and is not of suchstrength that when the member 28 is at the lower" limit of its downwardwill be able'to lift the member 28. The electromagnet 29 will 'only holdthe in the The member 27 has link 30 attached thereto which transmitsmotion to the-armature,

movement caused by gravity upona de- 1 '7 energization of thetranslating device 19, it'

31, and the armature 31 has the link 32 connected thereto so as to inturn transmit motion to the armature 33, so that all of the parts 30,31, 32 and 33 partake of the motion of the member 27 and movesynchronously with it. I

34 designates a generator of alternating current energy to which areconnected the line wires and 36 extending the length of the trackway. Atsuitable points transformers as 37 are connected across the line wiresand 36, each having a primary winding 38 and a secondary winding composed of two portions, 39 and 40. One terminal of the secondary portion39 is connected by a wire 53 directly to a track rail, as 2. The otherterminal of the secondary portion 39 is connected to one terminal of thesecondary portion 40, and they are both connected to a wire 41 connectedto a switch arm 42. secondary portion is connected by means of wire 43to the switch arm 44. Switch arms 42 and 44 are movable into and out ofengagement with the metallic strip 45, and the strip is connected bymeans of wire 46 to the ramp 17.

In carrying out this invention in practice la-ted that the differencesof potentials applied to the several ramps, as track 'will beautomatically governed by track relays in accordance with trafficconditions in advance, such as shown for example in my applicationSerial No. 6,248 filed February 5, 1915. For simplicity, however, theswitches 42 and 44 are shown on the accompanying drawing to control theartial circuits supplying differences of potential to the ramp 17, itbeing understood that these switches are illustrative of the functionsperformed by the circuit control- .lers which in practice are operatedautoondary portion matically by track relays.

Assume that the translating devices 19 of the train are deenergized;then if a shoe, as 11, contacts with a ramp, as 17, when a switch arm,as 44, is in contact with a metallic strip, as 45,

following circuits: one terminal of secondary portion 40, wire 43,switch arm 44. strip 45, wire 46, ramp 17, shoe 11, wire 47, bus 48,which extends throughout the train, and thence on each car along wire49, g 26, wire .50, impedance 51, wire 52, journal box 8, axle 7 wheel6, wire 53 and secondary portion 39 to the other terminal of the sec-40. If translating device 19 is deenergized, at the moment contact ismade between shoe 11 and ramp 17 it will thus be energized, and, causingits rotor 2 to turn, will cause member'27 to be the upper position," asshown in the figure, and so cause member 28 to come into operativerelation with electromagnet 29, and at the same time causes armatures 31and 32 The other terminal of the then current will flow in the 3 Thetranslating devices, raised to to be raised to the upper position, asshown in the figure.

Not only will the contact of shoe 11 with a ramp, as 17, which isconnected to the entire secondary of the transformer 37, causetranslating device 19 to be energized, but it will also cause all of theother translating devices similar to translating device 19, as 19, uponall of the other cars of the train, to be energized by current whichflows in a circuit as follows: secondary portion 40, wire 43, switch arm44, strip 45, wire 46, ramp 17, shoe 11, wire 47, bus 48, wire 49winding 26 wire 50, impedance 51 wire 52, journal box 8, axle 7 wheel 6rail 2, wire 53 and secondary portion 39 to the other terminal of thesecondary portion 40. Current flowing in the above traced path will thusenergize all the translating devices, as 19 located upon all the othercars of the train, whether or not the shoes, as 11 ,-of the other cars,are in contact with an energized ramp, as 1 The energization oftranslating device 19, and the movement of member 27, together with themovement of armature 31, causes a shunt circuit to be formed about theimpedance 51 so that the current which it was formerly stated flowedfrom wire 50 to wire 52 by means of impedance 51, will then flow fromwire 50 to wire 52 by means of wire 54, armature 31'and wire 55 to wire2 The result of forming und imedance 51 is to allow a smaller differenceof potential between the ramp rail 2 to energize the translating device19 sufficiently to cause it to hold the member 27 in the upper position,as shown, than is required to raise sition. If while the shoe 11 were onthe ramp 17 after current had flowed through the circuit including theswitch arm 44, and had so energized the translating device 19 that themember 27 is moved to the upper position, as shown, then if switch arm42 is put into contact with strip 45 and arm 44 is removed from incontact with strip 45, the translating device 19 will maintain the arm27 in the upper position, as shown, because, although a less differenceof potential exists between ramp 2, this smaller 17 and rail differenceof potential causes a current to flow through the shunt path aroundimpedance 51 instead of through the impedance 51, and consequently thepotential difference across the terminals of the winding 26 of thetranslating device 19 is maintained sufficiently high to enable thetranslating device to hold the member 27 in the upper position. as 19 onall of the other cars of the train. would, of course, for analogousreasons to those hereinbefore pointed out, be caused to maintain theirmovable members, as 27 in the upper position, as shown, by currentcaused to flow through the windings thereof, by reason of the differenceof potential between the ramp 17 and the rail 2.

After the member 27 has moved the member 28 to the upper position, asshown, it will be maintained in that position by reason of theenergization of magnet 29, which takes place just prior to the movementof the shoe 11 off from the ramp17, because, due to the inclined ends ofthe ramp 17 the shoe 11 moves downwardly as the car progresses, butbefore actually leaving the ramp it moves so far downwardly that themembers and 16 come into contact, whereby a circuit is formed asfollows: one terminal of the battery 56,.wire 57 electromagnet 29, wire58,

'member 15, member 16 and Wire 59 to the other terminal of the battery56. Current flowing in the above traced path will maintain electromagnet29 energized and the member 28 in the upper position, as shown, afterthe shoe 11 passes off fromthe ramp 17, so that the armature 33 will beheld in the upper position, as shown, so that the device for controllingin. any desired manner the movement of the vehicle, will be energized,so that it will in no way have any effect upon the movement of thevehicle.

It will be observed that the parts and circuits embodying this inventioncarry out the important principle of failure on the side of safety. Thetrain. control apparatus'60 is so constructed as to become activewhenever the currentnormally supplied to it is cut off, so that if thesource of current on the vehicle should fail, or some of the wiresbecome broken, this apparatus will be set into operation, resulting inthe control of'the train on the safe side. traveling between signal orcontrol points a under safe trafiic conditions, the train controlapparatus 60 is normally held in its inactive condition by currentflowing-in its control circuit which is closed by the armature 33 in itsupper position. The armature 33 has a tendency to open but is held inits closed position by the attraction of the electro-magnet 29, and thiselectro-magnet is in turn energized by current in a normally closedcircuit which is opened and closed by the shoe contacts 15 and 16 Whenthe train reaches a control or signal point, engagement of the contactshoe of each of its cars in turn with the ramp 17 breaks the normallyclosed circuit for the electro-magnet 29 at the shoe contacts 15 and 16,thereby permitting the armature 33 to drop and set the train controlapparatus 60 into operation unless something occurs to prevent thisaction. It should be noted that this tendency to set the train controlapparatus 60 into.

operation at each control point occurs irrespective of whether the rampat that point is energized or deenergized, so that a failure for. anyreason to receive a proceed impulse While the train isfrom a ramp willresult in the operation of the apparatus rather than its non-operation.The ramp will be supplied with alternating current in case trafiicconditions are safe and the trackway circuits are operating properly.This current passes through the winding 26 of the translating device 19,and since this device is responsive to alternating current, it will actto maintain the armature 33 closed.

It will thus be apparent that any ordinary failure of the devices orcircuits, such as.the breaking of a Wire or running down of the battery,will result in placing train control apparatus into operation. Toillustrate, if any of the wires 57 58 or 59 should break, the electro-magnet 39 wouldbecome deenergized, and this in turn would break thenormally closed circuit for maintaining the train control apparatus 60in its inactive condition.- If any of the wires in the track waycircuits, as the wires 16 or 53, should become broken for any reason,the ramp 17 would fail to be energized and the electro-magnetir device19 in turn would fail .to respond so that upon engagement of the contactshoes with such a ramp, the train control appa ratus would be set intooperation.

It should be noted that the electro-magceed impulse transmitted to thetrain from the track, is constructed so as to be respon sive only toalternating current. This is desirable because it prevents any improperoperation of this device 19 by current from any of the batteries onthe'train, and also by any stray or leakage direct current on the ramp17 which may exist because of an improper cross or connection with thethird rail or trolley wire.

-The continuous conductor or bus-line 48 extending between the severalvehicles of the .train which are equipped with the train controlapparatus performs the important function of enabling the control relayson the several vehicles to be simultaneously restored. This simultaneousrestoration is of cars with automatic train control apparatus and itsassociated controlling devices. When the motor cars are coupled into atrain, it is preferable to have the train control apparatus on each ofthe motor cars capable of stopping or retarding the train as a whole.

This adds to the safety of the system because some one of the severalapparatus-are sure to operate properly. With these contrain controlapparatus ditions. after the train control apparatus on the severalmotor cars of the train h ave been set into operation at acontrol point,it is important to restore them simultaneously at the next control pointunder safe traffic conditions, in order that the train as a whole mayproceed without delay. Otherwise, the train control apparatus on someone of the rear cars of the train would restrict progress of the trainas a whole until it had progressed far enough so that this rear carwould reach the control point and have its restored. This desirablefeature is provided for by this invention in a simple and reliablemanner. \Vith any one of the several contact shoes of the train on anenergized ramp, all of the control relays of the train will be restoredwithout. waiting until its own particular contact shoe strikes thisenergized ramp.

Applicant has herein illustrated the means for controlling the movementof the vehicle in the ordinary and conventional manner, as theparticular means used forms no part of the present invention, becausethe present invention is applicable to the control of any proper wellknown means forcontrolling the movement of a vehicle.

Although I have particularly described the construction of one physicalembodiment of my invention, and explained the operation and principlethereof; nevertheless, I desire to have it understood that the formselected is merely illustrative, but does not exhaust the possiblephysical embodiments of the idea of means underlying my invention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates, is

1. In an automatic train controlling system, in combination: a trackwayhaving a movable train composed of a plurality of cars thereon; adistinctive current relay on each car; means for simultaneouslyenergizing each of the said relays on each of the cars; and automatictrafiic rotecting means governed by each of said re ays.

2. In an automatic train controlling system, in combination: a trackwayhaving a movable train composed of a plurality of cars thereon; adistinctive current relay on each car; an arm moved to contactlngposition by an energization of said relay; means for holding saidcontacting arm in contact,

ing position; means for energizing said re lay; and automatic trafficprotecting means governed by said arm.

3. In a system for protecting railway traftic, in combination: arailroad track; a train including a number of vehicles adapted totravel, on said track; automatic trafiic protecting apparatus carried bysaid-train; a distinctive current relay on each vehicle for controllingsaid apparatus; means for controlling said relays on the severalvehicles of vices in cooperative relation carried by said trainsimultaneously; and devices in cooperative relation carried by saidtrain and located along said track for governing said last mentionedmeans.

4. In a system for protecting railway traffic, in combination: arailroad track; contact rails located along said track; means forcreating a difi'erence of potential between said contact rails and atrack rail of said track; a train including a number of vehicles adaptedto travel on said track; a continuous conductor extending between saidvehicles; a relay on each vehicle; a contact shoe carried by eachvehicle and arranged to engage said contact rails as said train passesalong said track; a partial circuit for governing the relay on eachvehicle terminating at said conductor and at the wheels of said vehicle;and means for electrically connecting each of said contact shoes withsaid conductor.

5. In a system for protecting railway traffic, in combination: arailroad track; atrain including a number of vehicles ada ted to travelon said track; automatic tra c protecting apparatus carried by saidtrain; an

alternating current relay on each vehicle arranged to control saidapparatus; electrically conductive paths constituting a circuitconnecting said relays in multiple; and desaid train and located alongthe track for energizing said energize said relays simultaneously.

6. In a system for protecting railway traffic, in combination: a trainincluding a number of vehicles; a control rela on each vehicle, a sourceof current on t e vehicle for energizing said relay; a device carried byeach vehicle and adapted when energized to govern the correspondingrelay, said device being incapable of being energized by current derivedfrom said source; and electrically conductive paths connectin thedevices on the several vehicles of the train, whereby said relays arecontrolled simultaneously.

fi 7 In a system for protecting railway trafa ber of vehicles; a relayon each vehic1e;'a continuous conductor extending between said vehicles,the relay on each vehicle being connected between said conductor and thewheels of the vehicle; and means including traflic controlled impulsedevices along the track for creating a difference of potential betweensaid conductor and a track rail of the track over which the vehiclepasses.

8. In a system for protecting railway traffic, in combination: arailroad track; a train including. a number of vehicles adapted totravel over the track; contact rails located at intervals along thetrack; means for creating a difference of potential between each incombination: a train including a numlast-mentioned circuit to therebyvehicle; contact ranged to make contact rails; an electrical conductorconnecting all of the contact shoes on the several vehicles of thetrain: and tratlic protecting means governed by the cooperation of thecontact shoes and the contact rails.

9. In a system for protecting railway traflie, in combination: a.vehicle; traflic protecting apparatus carried by the vehicle; analternating current relay for controlling said apparatus; a circuit forenergizing said relay including an impedance; a shunt for saidimpedance; and means governed by said relay for closing said shunt whenthe relay is energized.

10. In a system for protecting railway trailic, in combination; arailroad track: a rails located along the track; a contact shoe carriedby the vehicle; trafiic protecting apparatus carried by the vehicle; analternating current relay for governing said apparatus; apartial circuitfor energizing the relay terminating at the wheels of the vehicle and atsaid contact shoe; an impedance included in said partial circuit; ashunttor the impedance; means governed by said relay for closing theshunt when said relay is energized; and means for applying differencesof potential of difi'enent intensities across each contactrail and atrack rail of the track.

11. In a system for protecting railway traffic, in combination: a trainincluding a number of vehicles and a track therefor; contact railslocatedat intervals along the track and insulated therefrom; means forcreating a difference of potential alternating in character between saidcontact rails and the track rails; a contact shoe carried by eachvehicle and arranged to make electrical contact with said contact rails;a relay on each vehicle responsive to alternating current only; apartial circuit on each vehicle for governing its relay and terminatingat the shoe and frame of that vehicle; and means for electricallyconnecting the shoes on the several vehicles f the train, whereby saidrelays may be simultaneously energized.

12. In a system for protecting railway trailic, in combination: arailroad track; a train including a number of vehicles adapted to travelover said track; mechanism for automatically protecting the movement ofsaid train; a distinctive current relay carried by each vehicle; meanscontrolled by said relay for controlling said mechanism; electricallyconductive paths connecting said relays to enable them to be operatedsimultaneously; contact rails located at intervals along said track; acontact shoe carried by each of said vehicles and arranged to cooperatewith said contact rails; a partial circuit on each vehicle terminatingat each contact shoe and at the wheels thereof for governing thecorresponding relay; a source electrical contact with said ofdistinctive current capable of operating said relays; and a partialcircuit including this source of current and extending between a trackrail and a contact rail.

13. In a system for protecting railway traffic, in combination: arailroad track; contact rails located at intervals along said teach;means for creating differences of potential alternating in character andof different intensities between said contact rails and a track rail ofsaid track; a train including a number of vehicles adapted to travelover said track; a contact shoe carried by each vehicle and arranged tocooperate with said contact rails as said train passes along said track;a relay on each vehicle: a partial circuit for governing each relayterminating at said contact shoe and at the wheels of said vehicle, animpedance included in said partial circuit; a shunt for said impedance;means for closing said shunt when thecorresponding relay is energized:and means for electrically connecting the relays on the several vehiclesof said train to cause their simultaneous operation.

14:. In a system for protecting railway trafiic, in combination; arailroad track; a. vehicle adapted to travel over the track; traiiicprotecting apparatus on the vehicle having a tendency to assume itsactivecondition; electromagnetic means and a source of current fornormally maintaining said apparatus in its inactive condition; a distmctive current relay on the'vehicle operating, when energized, tomaintain said apparatus in its inactive condition independently of saidelectromagnetic means, said relay being incapable of operating on thesource of current used for operating said electromagnetic means; andmeans for supplying distinctive current to said relay at differentcontrol points along the track.

15. In a system for protecting railway trafiic, in combination: avehicle; trafiic protecting apparatus carried by the vehicle; means onthe vehicle for controlling said apparatus which is normally inactiveand has a tendency to assume its active condition; electromagnetic meansand a source of current carried by ing said first mentioned means in itsnormal inactive condition; a distinctive current relay carried by thevehicle and operating when energized to maintain the first mentionedmeans in its normally inactive condition independently of theelectromagnetic means, said relay being incapable of operating on thesource of current used for operating the electromagnetic means; andmeans carried by the vehiclein cooperative relation with devices locatedat intervals along the track for the vehicle for rendering theelectromagnetic means ineffective and for controlling the application ofthe distinctive current to said relay.

the vehicle for maintaini i said electromagnet 16. In a system forprotecting railway traffic, in combination: a vehicle; trafiicprotecting apparatus on the vehicle normally inactive and having atendency to assume its active condition; a movable member for conrollingsaid apparatus and biased to move from its normal position correspondingto the inactive condition of the apparatus; an electromagnet fornormally holding said member in its normal position,

being incapable of restoring the movable member to its normal positionafter it has once moved from that normal position; a normally closedcircuit for energizing said electromagnet; electromagnetic means forrestoring said movable member to its normal position; means lo cated atintervals along the track over which the vehicle passes and arranged tocooperate with the device carried by the vehicle to control theenergization of the last mentioned means and to simultaneously interruptsaid normally closed circuit.

17. In a system for protecting railway trafiic, in combination: avehicle; trafiic protectingapparatus on the vehicle, said apparatusbeing normally inactive and having a tendency to assume its activecondition; a relay operable by distinctive current; an armature operatedby said relay for controlling the apparatus, said armature ing a normalposition corresponding to the inactive condition of said apparatus andbeing biased to move from its normal position to an operating position,an electromagnet for holding said armature in its normal position, saidelectromagnet being incapable of restoring the armature from itsoperated position to its normal position; a normally closed circuit forenergizing the electromagnet and including a source of current differentfrom the distinctive current for operating the relay; and means forsimultaneously breaking said normally closed circuit and for controllingthe supply of distinctive current to said relay at predetermined.control points along the track over which the vehicle passes.

18. In an automatic train control system, a plurality of relays carriedby the several vehicles of a train, electrically conducting pathsconstituting a circuit for connecting said relays forsimultaneous-operation, and means comprising elements partly on thevehicle and partly along the track for transmitting current from thetrack to said circuit as each vehicle passes the control points alongthe track.

19. In an automatic train control system, a plurality of impulse devicescarried by the several vehicles of a train, said impulse devices beingadapted to cooperate with eleinents along the track to transmitelectrical energy from the track to the vehicles, electro-responsivemeans on each vehicle, a circuit connecting said means for simultaneousoperation. and connections for permitting electrical energy to beapplied to said circuit from the impulse devices on any one of thevehicles.

20. In an automatic train control system, trafiic protectin apparatuscarried on the vehicle, a movableelement for controlling the operationof said. apparatus, two electro-magnetic devices adapted to beseelectively operated by currents of different characteristics and eachcontrolling the movement of said element, a normally closed circuitincluding a source of current on the vehicle for energizing one of thedevices, means comprising elements partly on the vehicle and partlyalong the track for controlling the application of current from sourcesalong the track to the other device in accordance with trafficconditions, said last mentioned means also operating to break saidnormally closed circuit at each control point. 4

21. In an automatic train control system, a train, a plurality ofcontact shoes carried by the train, a conductor electrically connectingsaid contact shoes, and a plurality of relays on the train eachconnected between said conductor and the frame of the train.

22. In an automatic train control system, in combination: a trainincluding a number of vehicles; a contact shoe carried by each vehicle;a continuous conductor extending between the vehicles and electricallyconnected to the several contact shoes; a relay on each vehicleconnected between said conductor and the frame of the correspondingvehicle; ramps along the track with which said contact shoes cooperate;and means for establishing at times a difference of potential betweensaid ramps and the track rails.

23. In an automatic train control sys tem, in combination: a trainincluding a number of vehicles; a contact shoe carried by each vehicle;a conductor extending between the vehicles and electrically connected tothe several contact shoes; an alternating current relay on each vehicleconnected between said conductor and the frame of the correspondingvehicle; ramps along the track with which said contact shoes cooperate;and means for establishing at times an alternating difference ofpotential across each ramp and a track rail, the voltage of saidalternating difference of potential being varied. i

24'. In an automatic train control sys-' tern, a relay on avehicle, acircuit including said relay, means for changing the opposition to theflow of current in said circuit, and means operated by said relay forcontrolling said means.

25. In an'automatic train control. system, a train including a number ofvehicles each carrying a control device, electricconducting pathsconstituting a circuit for connecting said devices for simultaneousoperation, and means comprising impulse elements along the track adaptedto cooperate with impulse elements on the several vehicles, said meansbeing adapted to supply energy from the track to said circuit as avehicle passes a trackway element-dependent upon the existing conditionof that element.

26. In an automatic train control system, a vehicle, automatic traincontrol apparatus on the vehicle, a normally closed circuit on thevehicle for maintaining said apparatus inactive, a second normallyclosed circuit on the vehicle and electro-responsive means therein forgoverning the first normally closed circuit, a normally open circuit anda distinctive current electro-magnetic device therein adapted tomaintain or restore en-- ergization of the first mentioned normallyclosed circuit independently of the said second normally closed circuit,and impulse transmitting means partly ,on the vehicle and partly alongthe track acting to interrupt the second normally closed circuit atcontrol points alon the track and adapted to supply at times distinctivecurrent to'the normally open circuit.

27. In an automatic train control system, a vehicle, automatic traincontrol apparatus on the vehicle tending to assume an active condition,means including a normally closed circuit and a source of current on thevehicle for holding said apparatus in its inactive condition, a normallyopen circuit on the vehicle, a distinctive current electromagneticdevice included in the normally open circuit, and impulse devices atcontrol points along the track acting to discontinue the flow of currentinto the normally closed circuit and adapted to supply 'distinctivecurrent at times to the normally open circuit. r V

28.. In a system for protecting railway traflic, in combination: avehicle; a contact shoe carried by said vehicle; mechanism forcontrolling the movement of said vehicle; a relay for governing saidmechanism; a partial circuit terminating at the wheels of said vehicleand at said contact shoe for controlling said relay; means forincreasingthe opposltion to the flow of currentin said partial circuit; andmeansfor rendering said means effective when said relay'is deenergized.i

'29. In a system for protecting, railway traffic, in combination: avehicle; automatic trailic protecting apparatus carried by said vehicle;a relay forcontrolling said apparatus which is responsive to alternatingcur- ."ent; a contact shoe carried by said vehicle;

zwo partial circuits of different impedances For governing sa'd relayand terminating it said contacts e and at'the wheels source of currentlocated in the .ing said circuit 30. Railway traflic controllingapparatus I for a train made up of a plurality of vehicles, comprising atrain-governing electromagnetic means on each vehicle having a pick-upwinding and a holding winding, a circuit for the holding winding of eachelectro-magnetic means including a circuit controller on the samevehicle biased to closed position, a continuous conductor extendingthroughout the train, the pick-up winding of each electro-magnetic meansbeing connected across said conductor and ground, and means located inthe trackway for opening the said circuit controller oneach ve hicle andfor connecting a source of current with said continuous conductor andground.

31. Railway trafiic controlling apparatus for a train made up of aplurality ofvehicles, comprising a continuous conductor extendingthroughout the train, electromagnetic means on each vehicle having awinding constantly connected to said conductor, a source of currentlocated in the trackway, means for connecting said source to saidconductor, and a holding-circuit for each electro-magnetic meansincluding a source of current.

Railway traflic controlling apparatus for a train made up of a pluralityvehicles, comprising an electro-magnetic device on each vehicle having apick-up and a holding winding, a circuit for the holding windin of eachdevice including a circuit controlIer on the same vehicle biased toclosed position, a partial circuit on the train including the pick-upwinding of each device, and means located in the trackway for openingsaid circuit controllers and for at times supplying current to saidpartial circuit.

33. Railway trafiic controlling apparatus for a train made up of aplurality of vehicles, comprising an electro magnetic device on eachvehicle having a pick-up winding and a holding winding, a circuit forthe holding winding of each a circuit controller. on the same vehiclebiased to closed position, a continuous conductor extending throughoutthe train, the pickup winding of each device being connected across saidconductor and ground, a trackway, for opencontrollers and for consourcewith said conductor and device including and means located in thetrackway necting said ground. I I

I j WINTHROP K. HOWE. Witnesses:

SOPHIE LEVIN, ,Gnonon T. WHITNEY.

